Superheater boiler



July 24, 1928. 1,677,894

w. F. KEENAN. JR

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Patented July 24, 1928.

:UNITED STATES PATENT OFFICE.- i

WALTER FRANCIS KEENAN, JR., 0F PELHAM, NEW YORK, ASSIGNOR TO FOSTER WHEELER CORPORATION,- OF NEVI YORK, N. Y., A CORPORATION OF NEW YORK.

SUPERHEATER BOILER.

Application led March 31, 1924. Serial No. 703,061.

The primary object of the present invenf tion is to make a simple and eective combination of a superheater with a water tube boiler of the type comprising a pair of horizontal steam and water drums spaced relatively widely apart andl connected by horizontal circulating pipes, and also comprising horizontal water drums and water tubes connecting the water drums to one another and to one of the. steam and water drums. A further object of the invention is to provide an effective combination with a boiler of the type described and its superheating provisions, of an economizer so as to obtain a relatively high thermal eiiciency with a combination structure which is compact and relatively simple and durable and has provisions for ready inspection, repairs and renewals of the parts of the boiler with which such provisions are 'most important.

Of the drawings:

Fig. l is a sectional elevation of a portion of the boiler;

Fig. 2 is a partial section on the line 2-2 of Fig. l; i

Fig. 3 yis a view taken similarly to Fig. 2 but on a larger scale, showing a portion only of the apparatus shown in Fig. 2; and

Fig. 4: is an elevation taken similarly to Fig. Vl but on a larger scale illustrating detailso construction.

The boiler shown in the drawings comprises two steam and water drums A and B located with theiraxes approximately at the same level, and connected by an upper row of circulating tubes C which have horizontal body portions and down-turnedV end portions, and by lower circulating tubes D and` E. The tubes E comprise a short down-comer portion leading from the drum A and a longer upwardly inclined portion leading to the drum B so that the circulation through it is from the drum A to the drum B. The tubes D are generally similar to the tubes E but have their down-comer portions connected to the drum B and pass water from the latter to the drumV A. Located beneath the drumB is amud drum G connected to the drum B by a bank of tubes H the body portions of which are approximately vertical. Located beneath the drum A is an upper water drum I connected to the drum G by an inclinedl bank of tubes J and connected to the drum B by ya bank of inclined tubes F. The feed water is introduced into the tends beneath the tubes J and the heating` gases pass into the inter tube space of the bank of tubes J from the space L. Baiiies vM, M, M2, M3, M4, and M5 cause the gases entering the bank of tubes J toiiow upwardly alongside of and across the tubes J, thence upwardly across the portionsoi the tubes F, D, and E at the left of the bailes M2 and M2, thence over the top of the baille yM3 inthe space between the tubes C, D, and E, and thence down across the portions of the tubes D, E, and F at the right of the baiiies M2, M3, thence into the bank of'tubes H and downward alongside the tubes H at the left. hand side of the baille M5, and thence around the lower end of the baiiieM5 and upward along the tubes H at the right of the baille M5 to the outlet O. In so far as above-described, the boiler shown comprises nothing novel with me, but, on the contrary, is a con ventional -form of the known type ofv boiler which it is the purpose of the present invention to improve.

Inv accordance with the present invention, I arrange a superheater in the spiace between the upper circulating tubes C and the lower circulating tubes D and E. The superhea'ter is composed of U-shaped tube elements P having end portions P extending through one side wall of the boiler housing. The body-portions of the superheater elements P are horizontally; disposed and parallel in direction to the axes of the drums A, B, and I. f

Advantageously, as shown, the bodies 'of the elements P are of the well known Foster gilled tube type while the end portions P are bare. The portion vof the boiler housing wall through which' the end portion-s P extend is formed by a series ot' castings Q, one for each element P, with upper and lower apertures for" the corresponding pair of end portions P. Each casting Q is formed with a flange-like foot or base portion which rests on a metal sill Q2 and a similar flange or head at its upper end. The outer wall is formed of castings Q similar to the innercastings and interposed between the heads of the members Q, and the brickwork of the housing wall above them is a lintel plate advantageously made of relaying material Q3 such as Sil-o-cel.

tively short cast metal sections Q. The space between the walls formed by the parts Q is filled with asuitable heat insulat- Enter nally of the boiler housing the upper element ends B are connected to the superheater outlet header P5 while the lower element ends P are connected to the superheater inlet header P6. These headers, which are horizontally disposed and extend transversely to the aXes of the drums A and B, are supported from the boiler housing through brackets P7 to which they are clampedby clamping yokes P8. The boiler steam pipe K10 is -connected to one end of the superheater inlet header PG, and the steam delivery pipe. (not shown) is connected to the opposite end ofv the header P5. The legs of the elements P are spaced apart by interposed I-beams R, and the elements are supported at their ends remote from the headers and also intermediate their ends, on I-beams S suspended from the roof of the boiler housing by suspension bars or bolts S. Advantageously, as shown, the bank of superheatcr elements P is divided into two approximatelyequal sections or groups by the upper end of the baffle l 3 which extends between the two sections.V

Any usual or suitable provisions may be made for removing'furnace dust from the` superheater elements.

The superheater boiler construction described possesses important advantages from the practical standpoint. In the type of boiler illustrated, the main or-primary water circulation is from the Vsteam and water drum B down through the tubes H into the drum G, thence up through the tubes J, the drum I, and from the latter through the tubes F back to the drum B. In addition, there isa secondary water circulation from the drum A tothe drum B through the circulating tubes E and from the drum B to the drum A through the tubes D. Steam flows from the drum B, in which is the main steam disengaging surface of the boiler, into the outlet drum A through the tubes C. The described circulation per-- mits of the delivery of steam from the drum A through the steam pipe K10, which is not only quite dry but is somewhat superheated, even when the boiler is being forced or operated at a capacity much above its normal rating.

These characteristic vfeatures of the type of boiler shown, require the drums A and B to be separated widely enough so that all of the super-heating surface required for the amount of superheat ordinarily desired, may be obtained with a wide shallow bank of superheater elements such asis formed by the single row of ll-sh'aped elements shown. The character of the boiler baffling and the space provided between the superheater and the circulating tubes C insures a practically uniform distribution of heating gas up-ow across the superheater elements between the drum A andthe baffle M3 and a correspondd ing distribution of down-flow across the superheater elements between the baillelVl3 and the drumv B. This uniformity in distribution of the heating gases flowing vertically throughthe shallow horizontal bank of super-heater tubes insures effective and approximately equal use of all portions of the superheating surface, and minimizes the amount of heating surface required for a given superhcating effect and also avoids'the' tendency to excessive heat absorption and consequent overheating of a portion of the super-heating surface such as occurs when the How of the heating gases is unduly concentrated over a portion only of the superheater elements. The superheater element-S exercisea gas spreading effect on the flow through those elementswhich not only con'- tributes to the` desired horizontal distributionr of flow ofthe heating gases through the superheater elements, but' also to a desirable horizontal distribution of flow past the tubes F, E, and D, as well as in the upper portion` of the bank of tubes J. Aside from what may be called the thermal advantages of the superheater arrangement just explained, the superheater ar rangement is obviously desirable from amechanical standpoint because of its simplicity, durability and accessibility for inspection,

cleaning, or repairs. Access to the space bey tween the bank of superheater elements and the circulating tubes C is made possible by the provision ofthe manhole openings X. When it becomes necessary, as may sometimes be the case, to renew a superheater element, the formation of the metallic portion of the housing wall to whichthe superheater end portions eXtend out of the sectional castings Q, and the form of the seotional lintel plate Q, make it possible toremove the element to be renewed in a relatively simple manner by cutting the ends of the element loose from the headers P5 and P6, and breaking down a small portion of the brickwork of the housingl wall immedi-v ately above the element.

In the preferred construction illustrated, the heating gases leaving the boiler proper through the outlet O, pass downward through an economizer U to the economizer outlet U. The economizer U comprises a chamber or housing located alongside of, and as shown, directly in contact with the rear wall of the boiler housing. The economizer U, as shown, is of the known type of Foster economizer comprising ya bank of horizontally disposed gilled tube elements U2 connected at theiry ends by return bends (not shown) in such a manner as to provide multiple paths of flow each includingl tubes at successively higher levels between the economizer inlet header U3 and outlet header U4 which delivers water to the boiler feed water inlet K.

Vhile in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now lknown to me, it will be apparent to those' skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

I-Iaving now described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In a superheater boiler, the combination with horizontally disposed U-shaped superheater elements, of a housing wall comprising a pair of metal walls through which the ends of the elements extend, each formed in sections, one for each of said elements, and insulating material between said walls.

2. In a superheater boiler, the combination with horizontally disposed U-shaped superheater elements, of a housing wall comprising a pair of metal walls through which the ends of the elements extend, and each formed in sections, one for each of said elements, Aeach lsection being formed with apertures through which the corresponding ends of the element project, and insulating material between said walls.

3. In a superheater boiler, the combination with horizontally disposed U-shaped superheater elements of a housing wall comprising a pair of metal walls through which the ends of the elements extend, each wall formed in sections, one for each of said elements, insulating material between said walls and a sectional lintel plate resting on top of said sections and brickwork supported on said lintel plates. v

Signed at New York city, in the county of New York and State of New York, this 29th day of March, A. D., 1924.

WALTER FRANCIS KEENA N, JR. 

